This design was used in the initial experiments to investigate
its feasibility as a vapor-generation method for Hg. In experiments
with this design, the sample was mixed with the blank solution
when it was introduced into the cell. Therefore, the dominant
source of dead volume was the solution volume (about 15 mL).
In this case, the cell acts as an exponential dilution flask with a
very long (at least 20 min) wash-out time. To overcome this
limitation, a more compact cell (gas-phase internal volume of about
3 mL) was developed (cf. Figure 1B). In this design, the sample
solution is delivered through a glass capillary, which is conveniently
adapted from a 10-μL disposable micropipet (Fisher
Scientific Co., Pittsburgh, PA) with a 1.1 mm outer diameter and
0.38 mm inner diameter. A portion of the solution that is not
vaporized by the discharge overflows into a glass waste reservoir;
this overflow provides an electrical connection between the
discharge and the solution in the reservoir. In this case, the
discharge is sustained between the anode and the outlet of
the capillary tube.